What Does P1855 Mean?
The transmission control module has detected an open circuit in transfer case contact plate 'C'. This indicates a break in electrical continuity preventing proper communication or control of the transfer case engagement mechanism.
Common Causes
35%
Broken or disconnected wiring between TCM and transfer case contact plate 'C'
30%
Corroded or damaged connector at transfer case contact plate 'C'
20%
Failed transfer case contact plate 'C' assembly
10%
Damaged TCM connector or internal TCM fault
5%
Faulty transfer case motor/actuator assembly
Diagnostic Steps
1
Step 1: Visually inspect transfer case contact plate 'C' connector for corrosion, damage, or disconnection
2
Step 2: Check continuity of wiring harness between TCM and transfer case contact plate 'C' using multimeter
3
Step 3: Test voltage supply at contact plate 'C' connector with key on, engine running
4
Step 4: Inspect TCM connector for bent pins, corrosion, or terminal push-out
5
Step 5: Test transfer case contact plate 'C' resistance values according to manufacturer specifications
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
The transmission control module has detected an open circuit in transfer case contact plate 'C'. This indicates a break in electrical continuity preventing proper communication or control of the transfer case engagement mechanism.
The most common cause of P1855 (Transmission Transfer Case Contact Plate 'C' Open Circuit) is: Broken or disconnected wiring between TCM and transfer case contact plate 'C'
Typical repair costs for P1855 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may be stuck in one drive mode (2WD or 4WD) and could exhibit unexpected drivetrain behavior. Avoid off-road use or severe weather conditions until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1855 to identify the root cause.
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Quick Info
Category
Powertrain
System
Transfer Case / 4WD System
Difficulty
Type
Manufacturer
Recommended Tools
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